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AN2755 400 W FOT-controlled PFC pre-regulator with the L6562A


AN2755 Application note
400 W FOT-controlled PFC pre-regulator with the L6562A
Introduction
This application note describes an demonstration board based on the transition-mode

PFC controller L6562A and presents the results of its bench demonstration. The board implements a 400 W, wide-range mains input PFC pre-conditioner suitable for ATX PSU, flat screen displays, etc. In order to allow the use of a low-cost device like the L6562A at this power level, usually prohibitive for this device, the chip is operated with fixed-off-time control. This allows continuous conduction mode operation, normally achievable with more expensive control chips and more complex control architectures. Figure 1. Demonstration board (EVL6562A-400W)

July 2008

Rev 1

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Contents

AN2755

Contents
1 2 Main characteristics and circuit description . . . . . . . . . . . . . . . . . . . . . 5 Test results and significant waveforms . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.1 2.2 2.3 Harmonic content measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Inductor current in FOT and L6562A THD optimizer . . . . . . . . . . . . . . . . 10 Overvoltage protection and disable function . . . . . . . . . . . . . . . . . . . . . . 11

3 4 5 6 7 8

Layout hints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Audible noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Thermal measures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Conducted emission pre-compliance test . . . . . . . . . . . . . . . . . . . . . . 16 Bill of material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 PFC coil specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
8.1 8.2 8.3 General description and characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Mechanical aspect and pin numbering . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

9 10

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

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AN2755

List of tables

List of tables
Table 1. Table 2. Table 3. Table 4. Measured temperature table at 115 Vac and 230 Vac - full load . . . . . . . . . . . . . . . . . . . . 15 Bill of material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Winding characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

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List of figures

AN2755

List of figures
Figure 1. Figure 2. Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. Figure 8. Figure 9. Figure 10. Figure 11. Figure 12. Figure 13. Figure 14. Figure 15. Figure 16. Figure 17. Figure 18. Figure 19. Figure 20. Figure 21. Figure 22. Figure 23. Figure 24. Figure 25. Figure 26. Figure 27. Figure 28. Figure 29. Demonstration board (EVL6562A-400W) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EVL6562A-400W demonstration board electrical schematic . . . . . . . . . . . . . . . . . . . . . . . . 6 EVL6562A-400W compliance to EN61000-3-2 standard at full load . . . . . . . . . . . . . . . . . 7 EVL6562A-400W compliance to JEIDA-MITI standard at full load . . . . . . . . . . . . . . . . . . . . 7 EVL6562A-400W compliance to EN61000-3-2 standard at 70 W load . . . . . . . . . . . . . . . 7 EVL6562A-400W compliance to JEIDA-MITI standard at 70 W load . . . . . . . . . . . . . . . . . . 7 EVL6562A-400W input current waveform at 100 V - 50 Hz - 400 W load . . . . . . . . . . . . . . 8 EVL6562A-400W input current waveform at 230 V - 50 Hz - 400 W load . . . . . . . . . . . . . . 8 EVL6562A-400W input current waveform at 100 V - 50 Hz - 200 W load . . . . . . . . . . . . . . 8 EVL6562A-400W input current waveform at 230 V - 50 Hz - 200 W load . . . . . . . . . . . . . . 8 EVL6562A-400W input current waveform at 100 V - 50 Hz - 70 W load . . . . . . . . . . . . . . . 8 EVL6562A-400W input current waveform at 230 V - 50 Hz - 70 W load . . . . . . . . . . . . . . . 8 Power factor vs. Vin and load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 THD vs. Vin and load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Efficiency vs. Vin and load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Static Vout regulation vs. Vin and load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 EVL6562A-400W inductor current ripple envelope at 115 Vac - 60 Hz - full load . . . . . . . 10 EVL6562A-400W inductor current ripple (detail) at 115 Vac - 60 Hz - full load . . . . . . . . . 10 EVL6562A-400W inductor current ripple envelope at 230 Vac - 50 Hz - full load . . . . . . . 11 EVL6562A-400W Inductor current ripple (detail) at 230 Vac-50 Hz -full load. . . . . . . . . . . 11 EVL6562A-400W PCB layout (not scaled 1:1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Thermal map at 115 Vac - 60 Hz - full load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Thermal map at 230 Vac - 50 Hz - full load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 115 Vac and full load - phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 115 Vac and full load - neutral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 230 Vac and full load - phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 230 Vac and full load - neutral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Electrical diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Pin side view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

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Main characteristics and circuit description

1

Main characteristics and circuit description
The main characteristics of the SMPS are listed here below:
● ● ● ● ● ● ● ● ● ● ● ●

Line voltage range: Minimum line frequency (fL): Regulated output voltage: Rated output power: Maximum 2fL output voltage ripple: Hold-up time: Maximum switching frequency: Minimum estimated efficiency: Maximum ambient temperature: EMI: PCB type and size: Low profile design:

90 to 265 Vac 47 Hz 400 V 400 W 10 V pk-pk 22 ms 85 kHz 90 % 50 °C In accordance with EN55022 class-B Single side, 70 ?m, CEM-1, 148.5 x 132 mm 35 mm component maximum height (VDROP after hold-up time: 300 V) (Vin = 90 Vac, Pout = 400 W) (Vin = 90 Vac, Pout = 400 W)

The demonstration board implements a power factor correction (PFC) pre-regulator delivering 400 W continuous power on a regulated 400 V rail from a wide-range mains voltage and provides for the reduction of the mains harmonics, which allows meeting the European norm EN61000-3-2 or the Japanese norm JEIDA-MITI. This rail is the input for the cascaded isolated DC-DC converter that provides the output rails required by the load. The board is equipped with enough heat sinking to allow full-load operation in still air. With an appropriate airflow and without any change in the circuit, the demonstration board can easily deliver up to 450 W. The controller is the L6562A (U1), integrating all the functions needed to control the PFC stage. The L6562A controller chip is designed for transition-mode (TM) operation, where the boost inductor works next to the boundary between continuous (CCM) and discontinuous conduction mode (DCM). However, with a slightly different usage, the chip can operate so that the boost inductor works in CCM, hence surpassing the limitations of TM operation in terms of power handling capability. The gate-drive capability of the L6562A is also adequate to drive the MOSFETs used at higher power levels. This approach, which couples the simplicity and cost-effectiveness of TM operation with the high-current capability of CCM operation, is the Fixed-OFF-time (FOT) control. The control modulates the ON-time of the power switch, while its OFF-time is kept constant. More precisely, it uses the line-modulated FOT (LM-FOT) where the OFF-time of the power switch is not rigorously constant but is modulated by the instantaneous mains voltage. Please refer to [2] for a detailed description of this technique. The power stage of the PFC is a conventional boost converter, connected to the output of the rectifier bridge D2. It includes the coil L4, the diode D3 and the capacitors C6 and C7. The boost switch is represented by the power mosfets Q1 and Q2. The NTC R2 limits the inrush current at switch-on. It has been connected on the DC rail, in series to the output electrolytic capacitor, in order to improve the efficiency during low-line operation. Additionally, the splitting in two of output capacitors (C6 and C7) allows managing the AC current mainly by the film capacitor C7 so that the electrolytic can be cheaper as it just has to bear the DC part only.

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Main characteristics and circuit description

AN2755

At startup the L6562A is powered by the Vcc capacitor (C12) that is charged via the resistors R3 and R4. Then the L4 secondary winding (pins 8-11) and the charge pump circuit (R5, C10, D5 and D4) generate the Vcc voltage powering the L6562A during normal operation. The divider R32, R33 and R34 provides the L6562A multiplier with the information of the instantaneous voltage that is used to modulate the boost current. The divider R9, R10, R11, R12 & 13 is dedicated to sense the output. The Line-Modulated FOT is obtained by the timing generator components D6, C15, R15, C16, R16, R31, Q3. The board is equipped with an input EMI filter designed for a 2-wire input mains plug. It is composed of two stages, a common mode pi-filter connected at the input (C1, L1, C2, C3) and a differential mode pi-filter after the input bridge (C4, L3, C5). It also offers the possibility to easily connect a downstream converter. Figure 2. EVL6562A-400W demonstration board electrical schematic

?
J1 1 2

F1 8A/250V R1 1M 5 C1

CM 1.5mH-5A ~ L1 C2 470nF C3 680n F -X2 ~

D2 D15X B60 + C4

L3 DM-51uH- 6A D1 T 1N54 06 PQ40- 500uH 1-2 +400Vdc D3 S TTH8R06 8 11 C6 470nF-630V C7 330uF-450 V R2 J2 NT 2R5-S237 C 1 2 3 4 5

C5 5-6 470nF-63 0V

470nF-X 2

470n F 30V -6 -

90 - 265Vac

+400Vdc +400Vdc NC RT N RT N

+400Vo ut
R3 100K +400Vdc R9 R10 R5 4 7R

510k

510k

R102 0R0

R4 100K D4 LL4 148

C10 22N

R11 510k C11 470nF/50V R12 C13 22 0nF C14 2.2uF R14 47k 1 47K 12k R36 3R9 R17 6R8 R35 3R9 6 C15 68pF 5 LL41 48 D6 R13 D7 LL41 48 Q1 STP12NM 50FP C12 100uF/50V D5 BZX 85-C18

INV
2

VCC

8 7

COMP
3 4

L65 62A

GD GND ZCD

D8 LL4148 Q2 STP12NM 50FP

MULT CS

R18 6R8

R31 3k C16 120p F

R15 1k8 R1 6 3 0k

R19 1K0

R32 620k

R33 620k R34 10k C21 10nF

Q3 BC857C C20 330 pF R20 R21 0R47-1 W 0R4 7-1W R22 0R47-1W R23 0R4 7-1W

R101 0R0

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AN2755

Test results and significant waveforms

2
2.1

Test results and significant waveforms
Harmonic content measurement
One of the main purposes of a PFC pre-conditioner is the correction of input current distortion, decreasing the harmonic contents below the limits of the actual regulations. Therefore, the board has been tested according to the European rule EN61000-3-2 class-D and Japanese rule JEIDA-MITI class-D, at full load and 70 W output power, at both the nominal input voltage mains. As shown in the following figures of this page, the circuit is capable of reducing the harmonics well below the limits of both regulations from full load down to light load. 70 W of output power has been chosen because it approaches the lower power limit at which the harmonics have to be limited according to the mentioned rules.

Figure 3.

EVL6562A-400W compliance to EN61000-3-2 standard at full load
EN61000-3-2 class D limits

Figure 4.

EVL6562A-400W compliance to JEIDA-MITI standard at full load
JEIDA-MITI cla ss D lim its

?
10 Harm on ic cu rren t (A) 1

Me asure ments @ 230Va c Full load

Mea surem ents @ 100Vac Fu ll loa d 10 Harm on ic cu rren t (A)

1

0.1

0.1

0.01

0.01

0.001

0.001

0.0001 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 Har mon ic Ord er (n )

0.0001 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 H armo n ic Ord er (n )

Figure 5.

EVL6562A-400W compliance to Figure 6. EN61000-3-2 standard at 70 W load
EN61000-3-2 class D limits

EVL6562A-400W compliance to JEIDA-MITI standard at 70 W load
Measureme nts @ 100Vac 70W JEIDA-MITI cla ss D lim its

?
1 Harmo nic curre nt (A )

Measurements @ 230Vac 70W

?
1 Harmo nic c urren t (A)

0.1

0.1

0.01

0. 01

0. 001

0.001

0.0001 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 Harm onic Orde r (n)

0.0001 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 Harmo nic Ord er (n )

For user reference, waveforms of the input current and voltage at the nominal input voltage mains and different load conditions are shown in the following figures.

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Test results and significant waveforms

AN2755

Figure 7.

EVL6562A-400W input current waveform at 100 V - 50 Hz - 400 W load

Figure 8.

EVL6562A-400W input current waveform at 230 V - 50 Hz - 400 W load

Figure 9.

EVL6562A-400W input current waveform at 100 V - 50 Hz - 200 W load

Figure 10. EVL6562A-400W input current waveform at 230 V - 50 Hz - 200 W load

Figure 11. EVL6562A-400W input current waveform at 100 V - 50 Hz - 70 W load

Figure 12. EVL6562A-400W input current waveform at 230 V - 50 Hz - 70 W load

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Test results and significant waveforms The power factor (PF) and the total harmonic distortion (THD) have been measured too and the results are shown in Figure 13 and Figure 14. As visible, the PF at full load and half load remains close to unity throughout the input voltage mains range while, when the circuit is delivering 70 W, it decreases at high mains range. THD is low, remaining within 30 % at maximum input voltage.

Figure 13. Power factor vs. Vin and load

Figure 14. THD vs. Vin and load

?
1.05 1.00 0.95

?

35 30 25 20 15 10 5 0 80 130 Vin(Vac) 180 230 280 Pout = 400W Pout = 200W Pout = 70W

0.85 0.80 0.75 0.70 80 130 180 Vin (Vac) 230 280 Pout = 400W Pout = 200W Pout = 70W

The efficiency is very good at all load and line conditions. At full load it is always significantly higher than 90%, making this design suitable for high efficiency power supply. The measured output voltage variation at different line and load conditions is shown in Figure 16. As visible, the voltage is perfectly stable over the input voltage range. Just at 265 Vac and light load, there are negligible deviations of 1 V due to the intervention of the burst mode (for the "static OVP") function. Figure 15. Efficiency vs. Vin and load Figure 16. Static Vout regulation vs. Vin and load
404 403 402 Vout (Vdc) 401 400 Pout = 400W 399 398 397 80 130 180 Vin (Vac) 230 280 Pout = 200W Pout = 70W Pout = 15W

TH (% D )

0.90 PF

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Test results and significant waveforms

AN2755

2.2

Inductor current in FOT and L6562A THD optimizer
The following figures show the waveforms relevant to the inductor current at different voltage mains. As visible in Figure 17 and Figure 19, the inductor current waveform over a line halfperiod is very similar to that of a CCM PFC. In Figure 18 and Figure 20 the magnification of the waveforms at the peak of the sine wave shows the different ripple current and off-times, which is modulated by the input mains voltage. We can also note the transition angle from DCM to CCM that occurs closer to the zero-crossing of the current sine wave at low mains and moves toward the top if the circuit is working at high mains.

Figure 17. EVL6562A-400W inductor current Figure 18. EVL6562A-400W inductor current ripple envelope at 115 Vac - 60 Hz ripple (detail) at 115 Vac - 60 Hz full load full load

● ● ●

CH1: Q1/Q2 drain voltage CH2: I L inductor current ripple envelope CH3: MULT voltage - pin #3

● ● ●

CH1: Q1/Q2 drain voltage CH2: I L inductor current ripple envelope CH3: MULT voltage - pin #3

On both the drain voltage traces shown in Figure 17 and Figure 19, close to the zerocrossing points of the sine wave, it is possible to note the action of the THD optimizer embedded in the L6562A. It is a circuit that minimizes the conduction dead-angle occurring to the AC input current near the zero-crossings of the line voltage (crossover distortion). In this way, the THD (Total Harmonic Distortion) of the current is considerably reduced. A major cause of this distortion is the inability of the system to transfer energy effectively when the instantaneous line voltage is very low. This effect is magnified by the high-frequency filter capacitor placed after the bridge rectifier, which retains some residual voltage that causes the diodes of the bridge rectifier to be reverse-biased and the input current flow to temporarily stop. To overcome this issue the device forces the PFC pre-regulator to process more energy near the line voltage zero-crossings as compared to that commanded by the control loop. This results in both minimizing the time interval where energy transfer is lacking and fully discharging the high-frequency filter capacitor after the bridge. Essentially, the circuit artificially increases the ON-time of the power switch with a positive offset added to the output of the multiplier in the proximity of the line voltage zero-crossings. This offset is reduced as the instantaneous line voltage increases, so that it becomes negligible as the line voltage moves toward the top of the sinusoid.

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Test results and significant waveforms To maximally benefit from the THD optimizer circuit, the high-frequency filter capacitors after the bridge rectifier should be minimized, compatibly with EMI filtering needs. A large capacitance, in fact, introduces a conduction dead-angle of the AC input current in itself thus reducing the effectiveness of the optimizer circuit.

Figure 20. EVL6562A-400W Inductor current Figure 19. EVL6562A-400W inductor current ripple envelope at 230 Vac - 50 Hz ripple (detail) at 230 Vac-50 Hz full load full load

● ● ●

CH1: Q1/Q2 drain voltage CH2: I L inductor current ripple envelope CH3: MULT voltage - pin #3

● ● ●

CH1: Q1/Q2 drain voltage CH2: I L inductor current ripple envelope CH3: MULT voltage - pin #3

2.3

Overvoltage protection and disable function
The L6562A is equipped by an OVP, monitoring the current flowing through the compensation network and entering in the error amplifier (pin COMP, #2). When this current reaches about 24 ?A the output voltage of the multiplier is forced to decrease, thus reducing the energy drawn from the mains. If the current exceeds 27 ?A, the OVP is triggered (dynamic OVP), and the external power transistor is switched off until the current falls approximately below 7 ?A. However, if the overvoltage persists (e.g. in case the load is completely disconnected), the error amplifier eventually saturates low hence triggering an internal comparator (static OVP) that keeps the external power switch turned off until the output voltage comes back close to the regulated value. The OVP function described above is able to handle abnormal overload conditions, i.e. those resulting from an abrupt load/line change or occurring at startup. The INV pin doubles its function as a non-latched IC disable. A voltage below 0.2 V shuts down the IC and reduces its consumption to a lower value. To restart the IC, the voltage on the pin must exceed 0.45 V. The main usage of this function is a remote ON/OFF control input that can be driven by a PWM controller for power management purposes. However it also offers a certain degree of additional safety since it causes the IC to shut down in case the lower resistor of the output divider is shorted to ground or if the upper resistor is missing or fails to open.

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Layout hints

AN2755

3

Layout hints
The layout of any converter is a very important phase in the design process that sometimes does not have enough attention from the engineers. Even if it the layout phase sometimes looks time-consuming, a good layout does save time during the functional debugging and the qualification phases. Additionally, a power supply circuit with a correct layout needs smaller EMI filters or less filter stages which allows consistent cost savings. The L6562A does not need any special attention to the layout, just the general layout rules for any power converter have to be carefully applied. Basic rules are listed below, using the EVL6562A-400W schematic as a reference. They can be used for other PFC circuits having any power level, working either in FOT or TM control. 1. Keep power and signal RTNs separated. Connect the return pins of componentcarrying high currents such as C4, C5 (input filter), sense resistors, and C6, C7 (output capacitors) as close as possible. This point is the RTN star point. A downstream converter must be connected to this return point. Minimize the length of the traces relevant to L3, boost inductor L4, boost rectifier D4 and output capacitor C6 and C7. Keep signal components as close as possible to each L6562A relevant pin. Specifically, keep the tracks relevant to pin #1 (INV) net as short as possible. Components and traces relevant to the error amplifier have to be placed far from traces and connections carrying signals with high dv/dt like the MOSFET drains (Q1 and Q2). Connect heat sinks to power GND. Add an external shield to the boost inductor and connect it to power GND. Connect a ceramic capacitor (100 ÷ 470 uF) to pin #8 (Vcc) and to pin #6 (GND) and close to the L6562A. Connect pin #6 (GND) to the RTN star point (see 1).

2. 3.

4. 5. 6.

Figure 21. EVL6562A-400W PCB layout (not 1:1 scaled)
?

PFC PRECONDITIO NER USING L6562A FO T

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Audible noise

4

Audible noise
Differential mode currents in a circuit with high-frequency and low-frequency components (like in a PFC) may produce audible noise due to intermodulation between operating frequency and mains line frequency. The phenomenon is produced because of mechanical vibration of reactive components like capacitors and inductors. Current flowing in the winding can cause the vibration of wires or ferrite which produces buzzing noise. Therefore to avoid this noise, boost and filter inductors have to be wound with correct wire tension, and the component has to be varnished or dipped. Frequently, X-capacitors and filter capacitors after the bridge generate acoustic noise because of the AC current that causes the electrodes to vibrate which produces buzzing noise. Thus, in order to minimize the AC current, inserting a differential mode (pifilter between the bridge and the boost inductor) helps to reduce the acoustic noise and additionally the EMI filter benefits. This type of filter decreases significantly the ripple current that otherwise has to be filtered by the EMI filter. The capacitors to select are polypropylene, preferably dipped type, because boxed ones are generally more at risk to generate acoustic noise. The grounding of the boost inductor may help, because we decrease the emissions from the most efficient "antenna" of our circuit. In fact, in case of improper layout, some picofarads of layout parasitic capacitance, together with the very high dV/dt of the MOSFET drain voltage, may inject noise somewhere in the circuit.

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Thermal measures

AN2755

5

Thermal measures
In order to check the design reliability, a thermal mapping by means of an IR camera was done. Figure 22 and 23 show thermal measures on the board component side at nominal input voltages and full load. Some pointers visible on the pictures placed across key components show the relevant temperature. Table 1 provides the correlation between measured points and components for both thermal maps. The ambient temperature during both measurements was 27 °C. According to these measurement results, all components of the board are working within their temperature limits. Figure 22. Thermal map at 115 Vac - 60 Hz - full load
80.6 °C 73.9 67.2 60.5 53.8 47.1 40.4 33.7 26.9

Figure 23. Thermal map at 230 Vac - 50 Hz - full load
79.9 °C 73.2 66.6 60.0 53.3 46.7 40.0 33.4 26.8

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Thermal measures

Table 1.
Point A B C D E F G H I

Measured temperature table at 115 Vac and 230 Vac - full load
Component D2 Q2 Q1 D3 C7 L1 L3 L4 – CORE L4 - WINDING Temperature at 115 Vac 64.7 °C 76.5 °C 74.1 °C 72.8 °C 41.0 °C 58.5 °C 59.2 °C 57.0 °C 65.1 °C Temperature at 230 Vac 51.3 °C 62.0 °C 61.9 °C 65.6 °C 41.5 °C 43.5 °C 50.6 °C 56.5 °C 60.9 °C

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Conducted emission pre-compliance test

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6

Conducted emission pre-compliance test
The following figures show the peak measurement of the conducted noise at full load and nominal mains voltages. The limits shown in the diagrams are EN55022 class-B which is the most popular rule for domestic equipment using a two-wire mains connection. As visible in the diagrams, in all test conditions there is a good margin of the measures with respect to the limits.

Figure 24. 115 Vac and full load - phase

Figure 25. 115 Vac and full load - neutral

Figure 26. 230 Vac and full load - phase

Figure 27. 230 Vac and full load - neutral

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Bill of material

7
Table 2.
Ref. Des. C1 C10 C11 C12 C13 C14 C15 C16 C2 C20 C21 C3 C4 C5 C6 C7 C8 C9 D1 D2 D3 D4 D5 D6 D7 D8 F1 J1 J2 JP101

Bill of material
Bill of material
Part typepart value 470 nF - X2 22 nF 470 nF 100 uF 220 nF 2.2 uF 100 pF 120 pF 470 n F - X2 330 pF 10 nF 680 nF - X2 470 nF / 630 V 470 nF / 630 V 470 nF / 630 V 330 uF / 450 V RES RES 1N5406 D15XB60 STTH8R06 LL4148 BZX85-C18 LL4148 LL4148 LL4148 8A/250V Case/ Package DWG 1206 1206 DIA8X11 (MM) 0805 1206 0805 0805 DWG 0805 1206 DWG DWG DWG DWG DIA 35x35 (MM) DWG Not used DWG DO-201 DWG TO-220FP MINIMELF MINIMELF MINIMELF MINIMELF MINIMELF 5x20 MM Standard recovery rectifier Rectifier bridge Ultrafast high voltage rectifier Fast switching diode Zener diode Fast switching diode Fast switching diode Fast switching diode 8 A mains input fuse 3-pins conn. (central rem.) P 3.96 KK series Molex 5-pins conn. (central rem.) P 3.96 KK series JUMPER Wire jumper Wickmann Vishay Vishay Shindengen STMicroelectronics Description X2 film capacitor R46-I 3470--M1100 V SMD cercap - general purpose 50 V SMD cercap - general purpose Aluminium elcap - YXF SERIES 105 °C 50 V SMD cercap - general purpose 50 V SMD cercap - general purpose 50 V SMD cercap - general purpose 50 V SMD cercap - general purpose X2 film capacitor R46-I 3470--M150 V SMD cercap - general purpose 50 V SMD cercap - general purpose X2 film capacitor R46-I 3680--M1Film capacitor MKP - B32653A6474J Film capacitor MKP - B32653A6474J Film capacitor MKP- B32653A6474J Aluminium elcap - LLS series - 85 °C Supplier ARCOTRONICS AVX AVX Rubycon AVX AVX AVX AVX Arcotronics AVX AVX Arcotronics EPCOS EPCOS EPCOS Nichicon

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Bill of material Table 2.
Ref. Des. JP102 L1 L2 L3 L4 Q1 Q2 Q3 R1 R10 R11 R12 R13 R14 R15 R16 R17 R18 R19 R2 R20 R21 R22 R23 R25

AN2755

Bill of material (continued)
Part typepart value JUMPER CM-1.5 mH-5 A RES DM-51 uH-6 A PQ40-500 uH STP12NM50FP STP12NM50FP BC857C 1 M5 510 k 510 k 47 k 12 k 47 k 1 k8 30 k 6R8 6R8 1 K0 NTC 2R5 0R47-1 W 0R47-1 W 0R47-1 W 0R47-1 W RES DWG DWG DWG DWG TO-220FP TO-220FP SOT-23 AXIAL 1206 1206 0805 0805 0805 0805 0805 0805 0805 1206 DWG AXIAL AXIAL AXIAL AXIAL 1206 Case/ Package Description Wire jumper CM choke - LFR2205B Not used Filter inductor - LSR2306-1 Delta electronics PFC inductor - 86H-5410B N-channel power MOSFET STMicroelectronics N-channel power MOSFET Small signal BJT - PNP HV resistor SMD STD film res - 1% - 250 ppm / °C SMD STD film res - 1% - 250 ppm / °C SMD STD film res - 1% - 250 ppm / °C SMD STD film res - 1% - 250 ppm / °C SMD STD film res - 5% - 250 ppm / °C SMD STD film res - 1% - 100 ppm / °C SMD STD film res - 1% - 100 ppm / °C SMD STD film res - 5% - 250 ppm / °C SMD STD film res - 5% - 250 ppm / °C SMD STD film res - 5% - 250 ppm / °C NTC resistor 2R5 S237 Axial res - 5% - 250 ppm / °C Axial res - 5% - 250 ppm / °C BC components Axial res - 5% - 250 ppm / °C Axial res- 5% - 250 ppm / °C Not used EPCOS BC components Vishay Delta electronics Supplier

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AN2755 Table 2.
Ref. Des. R3 R31 R32 R33 R34 R35 R36 R4 R5 R9 R101 R102 U1

Bill of material Bill of material (continued)
Part typepart value 100 K 3k 620 k 620 k 10 k 3R9 3R9 100 K 47 R 510 k 0R0 0R0 L6562AD Case/ Package 1206 0805 1206 1206 1206 0805 0805 1206 1206 1206 1206 1206 SO-8 Description SMD STD film res - 5% - 250 ppm / °C SMD STD film res - 1% - 100 ppm / °C SMD STD film res - 5% - 250 ppm / °C SMD STD film res - 5% - 250 ppm / °C SMD STD film res - 5% - 250 ppm / °C SMD STD film res - 5% - 250 ppm / °C BC components SMD STD film res - 5% - 250 ppm / °C SMD STD film res - 5% - 250 ppm / °C SMD STD film res - 5% - 250 ppm / °C SMD STD film res - 1% - 250 ppm / °C SMD STD film res - 5% - 250 ppm / °C SMD STD film res - 5% - 250 ppm / °C Transition-mode PFC controller STMicroelectronics Supplier

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PFC coil specification

AN2755

8
8.1

PFC coil specification
General description and characteristics
● ● ● ● ●

Application type: consumer, home appliance Inductor type: open Coil former: vertical type, 6+6 pins Max. temp. rise: 45 ?C Max. operating ambient temperature: 60 ?C

8.2

Electrical characteristics
● ● ● ● ●

Converter topology: boost PFC pre-regulator, FOT control Core type: PQ40-30 material grade PC44 or equivalent Max. operating frequency: 100 kHz Primary inductance: 500 ?H 10 % at 1 kHz - 0.25 V (a) Primary RMS current: 4.75 A

Figure 28. Electrical diagram

5-6 Primary 1-2

11 Auxiliary 8

Table 3.
Start pins 11 5-6

Winding characteristics
End pins 8 1-2 Number of turns 5 (spaced) 65 Wire type Single – G2 Multistrand – G2 Wire diameter 0.28? Litz 0.2? x 30 Notes Bottom Top

a. Measured between pins 1-2 and 5-6

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AN2755

PFC coil specification

8.3

Mechanical aspect and pin numbering
● ● ● ● ● ● ● ● ●

Maximum height from PCB: 31 mm Ferrite: Two symmetrical half cores, PQ40-30 Material grade: PC44 or equivalent Central leg air gap: ~1 mm Coil former type: vertical, 6+6 pins Pin distance: 5 mm Row distance: 45.5 mm Cut pins: 9 - 12 External copper shield: not insulated (for EMI reasons), connected to pin 11 (GND)

Figure 29. Pin side view
6 5 4 27.5 mm 3 2 1 57 mm 10 11 12 7 8 9 45 mm

Copper shield soldering line 10 mm Tinned copper wire

BARE COPPER SHIELD (NOT INSULATED): 10 mm x 0.05 mm

Soldering points 7 8 10 11

Manufacturer: P/N:

Delta electronics 86H-5410B

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References

AN2755

9

References
1. 2. 3. 4. 5. "L6562A transition-mode PFC controller" datasheet "Design of fixed-off-time-controlled PFC pre-regulators with the L6562", AN1792 "EVAL6562-375W demonstration board L6562-based 375W FOT-controlled PFC preregulator" AN1895 "L6561, enhanced transition-mode power factor corrector”, AN966 “400 W FOT-controlled PFC pre-regulator with the L6563”, AN2485

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AN2755

Revision history

10

Revision history
Table 4.
Date 30-Jul-2008

Document revision history
Revision 1 Initial release Changes

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AN2755

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